Fuel cell integration within a heat recovery steam generator

Abstract

Systems and methods are provided for incorporating molten carbonate fuel cells into a heat recovery steam generation system (HRSG) for production of electrical power while also reducing or minimizing the amount of CO 2 present in the flue gas exiting the HRSG. An optionally multi-layer screen or wall of molten carbonate fuel cells can be inserted into the HRSG so that the screen of molten carbonate fuel cells substantially fills the cross-sectional area. By using the walls of the HRSG and the screen of molten carbonate fuel cells to form a cathode input manifold, the overall amount of duct or flow passages associated with the MCFCs can be reduced.

The invention claimed is: 
     
       1. A heat recovery steam generator (“HRSG”) for producing electricity using an integrated molten carbonate fuel cell comprising an anode and cathode, the HRSG comprising:
 an enclosure that forms a flow path that extends between an inlet that receives a gas flow and an outlet that exhausts at least a portion of the received gas flow; 
 one or more heat exchangers extending into the flow path; and 
 a fuel cell screen located within the enclosure and comprising a plurality of molten carbonate fuel cells having cathode inlets, the fuel cell screen being oriented in the flow path so that the cathode inlets of the molten carbonate fuel cells receive substantially all of the received gas flow, the plurality of molten carbonate fuel cells also having a plurality of cathode outlets fluidly exposed to the flow path to discharge cathode exhaust to the flow path. 
 
     
     
       2. The HRSG of  claim 1 , wherein the fuel cell screen is located in the flow path downstream from a duct burner located within the HRSG and upstream from the one or more heat exchangers. 
     
     
       3. The HRSG of  claim 1 , wherein the fuel cell screen is located in the flow path downstream from a first heat exchanger of the one or more heat exchangers and upstream from a second heat exchanger of the one or more heat exchangers. 
     
     
       4. The HRSG of  claim 1 , wherein a first cross sectional area of the enclosure at the fuel cell screen is at least double a second cross-sectional area downstream of the first cross sectional area where the one or more heat exchangers are located. 
     
     
       5. The HRSG of  claim 1 , wherein the HRSG further comprises a second fuel cell screen comprising a second plurality of molten carbonate fuel cells. 
     
     
       6. The HRSG of  claim 1 , wherein a layer of the fuel screen comprises at least about 10 fuel cell stacks. 
     
     
       7. The HRSG of  claim 1 , wherein the plurality of molten carbonate fuel cells in the fuel cell screen comprises multiple layers of molten carbonate fuel cells, the multiple layers of molten carbonate fuel cells in the fuel cell screen being fluidly arranged to provide parallel processing of the received gas flow.